In water, these molecules spontaneously align â with their heads facing outward and their tails lining up in the bilayer's interior. Thus, the hydrophilic heads of the glycerophospholipids in a cell's plasma membrane face both the water-based cytoplasm and the exterior of the cell.
An MRI (magnetic resonance imaging) scan is an imaging test that uses powerful magnets and radio waves to create pictures of the body. It does not use radiation (x-rays). Single MRI images are called slices. The images can be stored on a computer or printed on film.
Breast MRI (magnetic resonance imaging) is a test that should not be used to distinguish between benign (noncancerous) and malignant (cancerous) areas, in lieu of a breast biopsy. Due to false positive results, performing this test may increase the number of breast biopsies that need to be performed. Although MRI may detect tumors in dense breast tissue, the presence of dense breast tissue is not a reason to have a breast MRI scan.